UA Researcher Explores Effect of Rising Sea Level, Carbon Dioxide Levels on Nation’s Coastal Wetlands

TUSCALOOSA, Ala. – A University of Alabama researcher is exploring the effects that rising sea level and greenhouse gases may have on the nation’s coastal wetlands.

Results of this research have appeared in two recent journal articles. These studies suggest that delicate wetlands may be able to withstand rising sea levels better than previously thought.

Dr. Julia Cherry, assistant professor in UA’s New College and biological sciences department, and collaborators with the U.S. Geological Survey and the Smithsonian Institution, co-authored a paper published in March in the Proceedings of the National Academy of Sciences. The study looks at processes controlling elevations in coastal marshes particularly vulnerable to sea-level rise.

The results in this study, conducted at the Wetland Elevated CO2 Experimental Facility in Lafayette, La., and at Kirkpatrick Marsh in the Chesapeake Bay, showed that elevated concentrations of carbon dioxide increased the rate of marsh elevation gain, primarily by stimulating plant root production.

Cherry’s co-authors are J. Adam Langley and Patrick Megonigal of the Smithsonian Environmental Research Center and Karen L. McKee and Donald R. Cahoon of the U.S. Geological Survey. The Proceedings of the National Academy of Sciences study can be found online at http://www.pnas.org/content/early/2009/03/25/0807695106.full.pdf+html?sid=2306500c-ce3c-4d74-8498-24740a967414.

A second paper Cherry co-wrote, published recently in the Journal of Ecology, reveals similar results of an experiment testing how increased levels of carbon dioxide, which plants absorb, affect certain marsh plants faced with stressors associated with sea-level rise, including increased salt levels and flooding.

“CO2 can offset flooding and salt stress for some plants and, by stimulating plant growth and soil building, can help some marshes counterbalance sea-level rise,” Cherry says.

The results suggest that increased carbon dioxide in our atmosphere may help some coastal marshes keep up with sea-level rise by stimulating belowground plant production, causing soil surfaces to rise. The rise in soil surfaces helps to mitigate the effects of a rising sea level in the short term, but continued increases in carbon dioxide will accelerate sea-level rise and overwhelm the potential positive effects of CO2 observed in these studies.

Cherry’s co-authors are McKee and James B. Grace of the U.S. Geological Survey’s National Wetlands Research Center. The Journal of Ecology study can be found online at http://www3.interscience.wiley.com/cgi-bin/fulltext/121527505/PDFSTART.

Both studies were part of a larger project funded by the U.S. Geological Survey’s Global Change Program.

For more information on these articles, contact Cherry at 205/348-8416 or julia.cherry@ua.edu.

New College and the department of biological sciences are a part of UA’s College of Arts and Sciences, the University’s largest division and the largest liberal arts college in the state. Students from the College have won numerous national awards including Rhodes Scholarships, Goldwater Scholarships and memberships on the USA Today Academic All American Teams.